1. Field of the Invention
The present invention relates to a washing machine, and more particularly, to a pulsator provided at a lower portion of a tub to form a water movement during its rotation and to a washing machine using the same.
2. Discussion of the Related Art
Generally, using water and detergent, washing machines are capable of performing washing, rinsing, and dewatering operations to separate dirt from clothes. Washing machines are typically classified into agitator, pulsator, and drum-type washing machines.
Agitator-type washing machines wash laundry by rotating a washing rod at the center of a washing tub in forward and reverse directions. Agitator-type washing machines have an excellent washing capabilities but are loud, generate excessive vibration, and can damage laundry.
Drum-type washing machines wash laundry by loading water, detergent, and laundry into a drum having a plurality of protruding tumbling ribs installed at an inner surface of the drum and rotating the drum at a low speed. Drum-type washing machines do not damage laundry, consume a small amount of water, and, after the washing operation is complete, laundry is not entangled. However, drum-type washing machines are deleteriously loud, consume a large amount of power, and require a relatively long amount of time to adequately wash laundry.
Pulsator-type washing machines wash laundry using forces generated between moving water and the laundry, wherein the water movement is typically generated by a disk-shaped pulsator rotating in forward and reverse directions. Pulsator-type washing machines have excellent washing capacities and can wash laundry in a relatively short amount of time. Further, pulsator-type washing machines generate a relatively low amount of noise and vibration and are inexpensive. Newly developed pulsator-type washing machines are able to avoid previously encountered problems of entangling and damaging laundry by replacing clutch-type driving systems with direct driving systems.
FIG. 1 illustrates a partial sectional view of a related art pulsator-type washing machine.
Referring to FIG. 1, a cylindrical outer tub (not shown) is provided within a cabinet 1 for containing water. An inner tub 2, rotatably provided within the outer tub, includes a plurality of holes 2a enabling water to flow between the inner and outer tubs. A pulsator 3 is provided at the inner, bottom region of the inner tub 2 and is coupled to a driving shaft (not shown) that is rotatable by means of a motor (not shown). A plurality of upwardly protruding washing ribs 3a are arranged on an upper surface of the pulsator 3 and radiate from the center of the pulsator 3. During operation, the pulsator 3 rotates in forward and reverse directions to move water horizontally to perform a washing operation. A top cover 4 is provided at an upper portion of the cabinet 1 and includes a lid 5 for closing/opening an opening exposing the interior of the washing machine. A filtering mesh 6 is provided for filtering lint generated during the washing operation.
When the pulsator 3 rotates, the horizontally moving water generates a friction capable of washing the laundry. Importantly, the direction of the moving water and energy generated by its movement heavily influences the capability of pulsator-type washing machines to effectively wash laundry. Since the water movement is primarily generated by the washing ribs 3a, there is generally a limit to the direction water can be moved. Specifically, movement of the washing ribs 3a can be controlled to adjust the horizontal direction the water moves and the energy associated by its horizontal movement. However, the washing ribs 3a are limited in their ability to effectively control any vertical movement of water, let alone the energy associated with its vertical movement.
Accordingly, in order to improve the performance of the pulsator-type washing machine, an improved pulsator, capable of creating highly energetic motion; in the water along both vertical and horizontal directions, must be provided.
In the related art pulsator washing machine described above, inner and outer surfaces of the inner tub 2 are covered by water. Accordingly, the inner tub 2 is formed out of a material having a strong corrosion resistance and a high metallic gloss such as stainless steel. The pulsator 3, provided at the lower portion of the inner tub 2 and moving the water, however, is formed of a synthetic resin having no metallic gloss. Accordingly, the interior of the related art pulsator-type washing machine has a low aesthetic quality due to the difference in material surface finishes.
Moreover, when the synthetic resin pulsator 3 rotates, metallic objects included within the laundry (e.g., buttons, zipper, coins, keys, etc.) often strike the upper surface of the pulsator 3, creating scratches and burrs on the upper surface of the synthetic resin pulsator 3. As a result, laundry may become damaged due to the scratches and burrs, and a large amount of lint may be generated during the washing operation.